(1) Field of the Invention
This invention relates to powered wheelchairs and in particular but not solely to wheelchairs which may be converted from manual propulsion to powered propulsion.
(2) Description of the Prior Art
The overwhelming majority of conventional wheelchairs in current use are designed to fold for easy transportation. Powered wheelchairs have generally been developed using conventional wheelchair designs as a basis and therefore mostly retain the folding features, although the addition of motors, controller and battery mountings tend to make them rather heavy and ungainly to lift. To combat this, a small number of manufacturers have developed detachable drive systems. However, these tend to fall in one of two categories; either low power units (often with only a single motor) or heavy one-piece drive units, which remain the heaviest part of the wheelchair to lift. In both categories it is only possible to fold the wheelchair after the drive unit has been removed, so that the option of transporting or storing it as a complete folded unit is lost. Some designs retain the ability to propel the wheelchair manually, which is an advantage for users with progressive disabilities or limited ability to propel themselves. However, this feature is usually confined to low power types.